Large or small embolic particles or emboli can be formed for a number of reasons in the left atrium or in other parts of the heart, such as can occur when surgically implanting prosthetic devices into a patient's anatomy. When such particles or emboli are present in the atrium, they have the potential to migrate toward the brain at the arch of the aorta, and can thereby impose potential risk of stroke. Thus, there is a need to provide devices and delivery systems that can filter or guard against undesired emboli migration within the heart or other bodily structures of a patient.